This invention relates to a boot-band, such as one made of rubber, resin, or the like, for fixing a boot, on a connecting member.
A boot-band, such as one made of rubber or resin, has been used as a part of automobiles and the like. The kind of boots discussed in the present specification include hollow cylindrical members, such as a hose or a tube. To fix this kind of boot on a mating member, a boot-band made of a metallic, belt-shaped member has been used. Previous models of this kind of boot-band, such as those described in Japanese Utility Model Publication No. H2-9195 or Japanese Patent No. 2538554, have been known.
The aforementioned previous models are referred to as bands of a caulking type. A band of this type has a metallic, belt-shaped band-body, which is curled into the shape of a ring. A hooking claw formed on the inner overlap portion of the band-body is to be hooked over the hole formed in the outer overlap portion. The ear portion of the band-body is plastically deformed by a jig under the condition that the hooking claw is hooked over the hole. In this way, the circumference of the band body of a band of this type is reduced, resulting in a design that provides the band-body with a binding power to clamp the member to be clamped.
In the case of such caulking-type boot-bands, higher rigidity of the ear portion is desirable because of the more-or-less spring-back that arises in the ear portion, even if the plastic deformation of the ear portion has reduced the circumference of the boot band to the desired level. For this reason, the aforementioned band of Japanese Utility Model Publication No. H2-9195 forms outwardly prominent, rib-like parts that protrude at the opposite ends of the ear portion along a line that is perpendicular to the circumference, as well as a dowel portion that sinks inwardly between the rib-like parts. In a similar but slightly different manner, the aforementioned band of Japanese Patent Publication No. 2538554 forms a shallow, dish-like sinking inwardly at the center of the bridge portion on the flat-shaped ear portion.
The aforementioned band of Japanese Utility Model Publication No. H2-9195 has a problem in that the outward prominence of the ear portion becomes too large because the whole ear portion buckles in an omega-shape when the ear portion is plastically deformed by a clamping tool to clamp the band. In order to make the ear portion less prominent, the upward deformation of the ear portion should be controlled by use of an improved clamping tool. In this case, however, there is a different problem, in that the loading that is necessary to deform (clamp) the ear portion is increased and the tool that is used accordingly needs to be larger and more specialized.
In contrast, the aforementioned band of Japanese Patent No. 2538554 has a problem that the whole ear portion is deformed to an omega-shape when clamped with a tool, especially with the opposite ends of the bridge portion being outwardly prominent, and with the amount of resilient deformation in the expanding direction of the band being increased. This is because the shallow, dish-like sinking on the ear portion does not result in high rigidity of the ear portion. In the case of a band of this kind, a larger clamping stroke could be obtained with an ear portion that is longer in the clamping direction. However, it has been actually impossible to make a longer ear portion, because a longer bridge portion causes the maximum height of the ear portion to be higher after the plastic deformation.
It should be noted that a more-rigid ear portion does not necessarily mean a better one. Too rigid a bridge portion can cause the leg portions to be more deformed than any other portion, and, consequently, the leg portions might be subject to more stress. Because the leg portions are damaged or thinned, the ear portion is weaker as a whole.
The object of the present invention, therefore, is to provide a boot-band whose ear portion is more rigid and less prominent after its deformation, and whose leg portions are prevented from being damaged.
To achieve the aforementioned object, the present invention is a metal boot-band that is belt-shaped, and whose band-body is curled into the shape of a ring to be set on a member that is to be clamped, and that is principally characterized in that it is equipped with (1) fixing portions that lock the outer overlap portion to the inner overlap portion of the band-body, and (2) an ear portion that can be plastically formed into a shape that reduces the circumference of the band-body, and that has (a) a pair of leg portions that protrude outward and that are formed in the circumferential direction on said band-body, and (b) a bridge portion that links the leg portions, and that in said ear portion are formed [1] rib-like parts that are inwardly bent at the opposite ends of the bridge portion, and [2] a dowel portion that inwardly sinks between the rib-like parts. Said rib-like parts have an arc-shape so that their inward prominence increases toward the middle of the bridge portion in the clamping direction, and they have a length that is 60% or more of the length of the bridge portion in the clamping direction, but not more than the length obtained by subtracting the length of the curved portion at the opposite ends of the bridge portion from the length of the bridge portion in the clamping direction. Said dowel, portion has a length that is as long as, or longer than, the length of the rib-like parts.
In the case of the boot-band of the present invention, which is composed of the aforementioned parts, it is possible to reduce the winding diameter or circumference of the band-body by forming the ear portion with a clamping tool. In the ear portion, mainly the leg portions are so formed because the other parts are made more rigid by the rib-like parts and the dowel portion. Because the rib-like parts have a length that is 60% or more of the length of the bridge portion in the clamping direction, but not more than the length obtained by subtracting the length of the curved portion at the opposite ends of the bridge portion from the length of the bridge portion in the clamping direction, and because the dowel portion has a length that is as long as, or longer than, the length of the rib-like parts, the rigidity decreases from the middle of the bridge portion in the clamping direction toward the leg portions, whereby the rigidity is prevented from changing excessively between the leg portions and the bridge portion.